1
|
Üveges B, Kalina C, Szabó K, Móricz ÁM, Holly D, Gabor CR, Hettyey A, Bókony V. Does the Glucocorticoid Stress Response Make Toads More Toxic? An Experimental Study on the Regulation of Bufadienolide Toxin Synthesis. Integr Org Biol 2023; 5:obad021. [PMID: 37435008 PMCID: PMC10331804 DOI: 10.1093/iob/obad021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/15/2023] [Accepted: 06/02/2023] [Indexed: 07/13/2023] Open
Abstract
Chemical defense is a crucial component of fitness in many organisms, yet the physiological regulation of defensive toxin synthesis is poorly understood, especially in vertebrates. Bufadienolides, the main defensive compounds of toads, are toxic to many predators and other natural enemies, and their synthesis can be upregulated by stressors, including predation risk, high conspecific density, and pollutants. Thus, higher toxin content may be the consequence of a general endocrine stress response in toads. Therefore, we hypothesized that bufadienolide synthesis may be stimulated by elevated levels of corticosterone (CORT), the main glucocorticoid hormone of amphibians, or by upstream regulators that stimulate CORT production. To test these alternatives, we treated common toad tadpoles with exogenous CORT (exoCORT) or metyrapone (MTP, a CORT-synthesis inhibitor that stimulates upstream regulators of CORT by negative feedback) in the presence or absence of predation cues for 2 or 6 days, and subsequently measured their CORT release rates and bufadienolide content. We found that CORT release rates were elevated by exoCORT, and to a lesser extent also by MTP, regardless of treatment length. Bufadienolide content was significantly decreased by treatment with exoCORT for 6 days but was unaffected by exposure to exoCORT for 2 days or to MTP for either 6 or 2 days. The presence or absence of predation cues affected neither CORT release rate nor bufadienolide content. Our results suggest that changes in bufadienolide synthesis in response to environmental challenges are not driven by CORT but may rather be regulated by upstream hormones of the stress response.
Collapse
Affiliation(s)
| | - C Kalina
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
- Department of Ecology, Institute of Biology, University of Veterinary Medicine, István u. 2, 1078 Budapest, Hungary
| | - K Szabó
- Division of Clinical Immunology, Department for Internal Medicine, Faculty of Medicine, University of Debrecen, Móricz Zsigmond út 22, 4032 Debrecen, Hungary
| | - Á M Móricz
- Department of Pathophysiology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
| | - D Holly
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
| | - C R Gabor
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
- Department of Biology, College of Science and Engineering, Texas State University, 601 University Dr., San Marcos, TX 78666, USA
| | - A Hettyey
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
| | - V Bókony
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, 1022 Budapest, Hungary
- Department of Ecology, Institute of Biology, University of Veterinary Medicine, István u. 2, 1078 Budapest, Hungary
| |
Collapse
|
2
|
Kaczmarek JM, Kaczmarski M, Mazurkiewicz J, Kloskowski J. Forget the toad and eat the frog: no associational protection against fish from a chemically defended toad to a later-breeding anuran species. ETHOL ECOL EVOL 2022. [DOI: 10.1080/03949370.2021.1967455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jan M. Kaczmarek
- Department of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, Poznań 60-625, Poland
| | - Mikołaj Kaczmarski
- Department of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, Poznań 60-625, Poland
| | - Jan Mazurkiewicz
- Department of Inland Fisheries and Aquaculture, Poznań University of Life Sciences, Wojska Polskiego 71C, Poznań 60-625, Poland
| | - Janusz Kloskowski
- Department of Zoology, Poznań University of Life Sciences, Wojska Polskiego 71C, Poznań 60-625, Poland
| |
Collapse
|
3
|
Siddiqui JA, Bamisile BS, Khan MM, Islam W, Hafeez M, Bodlah I, Xu Y. Impact of invasive ant species on native fauna across similar habitats under global environmental changes. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:54362-54382. [PMID: 34405331 DOI: 10.1007/s11356-021-15961-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Biotic invasions can predominantly alter the dynamics, composition, functions, and structure of natural ecosystems. Social insects, particularly ants, are among the most damaging invasive alien species. Invasive ant species are among the supreme threats to ecosystems. There are about 23 species of invasive ants recorded worldwide, according to the ant invasive databases. The ecological impacts of invasive ants comprise predation, hybridization, and competition with native species that changes the ecosystem processes with the biodiversity loss and upsurge of pests. The effects of invasion on native fauna in the same habitats might be catastrophic for the native community through various ecological mechanisms, e.g., habitat disturbance, resource competition, limiting the foraging activity of native species, and various other indirect mechanisms of invasive species. Invasive species may have harmful impacts on habitats and devastating effects on natural flora and fauna, and stopping these new species from being introduced is the most effective way to deter future invasions and maintain biodiversity. This paper reviews the literature to evaluate the effects of invasive ant species on the native species, including vertebrates, invertebrates, and plants sharing the same habitats as the non-native species under global environmental changes. We also highlighted the various management strategies that could be adopted in minimizing the adverse effects of these invasive ant species on the natural ecosystem. To this end, strategies that could regulate the mode and rate of invasion by these alien ant species are the most effective ways to deter future invasions and maintain biodiversity.
Collapse
Affiliation(s)
- Junaid Ali Siddiqui
- Red Imported Fire Ant Research Centre, South China Agricultural University, Guangzhou, 510642, Guangdong, China
| | - Bamisope Steve Bamisile
- Red Imported Fire Ant Research Centre, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
| | - Muhammad Musa Khan
- Key Laboratory of Bio-Pesticide Innovation and Application, Engineering Research Centre of Biological Control, South China Agricultural University, Guangzhou, China
| | - Waqar Islam
- College of Geography, Fujian Normal University, Fuzhou, 350007, China
| | - Muhammad Hafeez
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Imran Bodlah
- Insect Biodiversity and Conservation Group, Department of Entomology, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan
| | - Yijuan Xu
- Red Imported Fire Ant Research Centre, South China Agricultural University, Guangzhou, 510642, Guangdong, China.
| |
Collapse
|
4
|
Few Impacts of Introduced Cutthroat Trout (Oncorhynchus clarki) on Aquatic Stages of Boreal Toads (Anaxyrus boreas boreas). J HERPETOL 2021. [DOI: 10.1670/20-033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
5
|
Kaczmarek JM, Kaczmarski M, Mazurkiewicz J, Kloskowski J. Numbers, neighbors, and hungry predators: What makes chemically defended aposematic prey susceptible to predation? Ecol Evol 2020; 10:13705-13716. [PMID: 33391674 PMCID: PMC7771146 DOI: 10.1002/ece3.6956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 09/17/2020] [Accepted: 09/21/2020] [Indexed: 11/23/2022] Open
Abstract
Many chemically defended aposematic species are characterized by relatively low toxin levels, which enables predators to include them in their diets under certain circumstances. Knowledge of the conditions governing the survival of such prey animals-especially in the context of the co-occurrence of similar but undefended prey, which may result in mimicry-like interactions-is crucial for understanding the initial evolution of aposematism. In a one-month outdoor experiment using fish (the common carp Cyprinus carpio) as predators, we examined the survival of moderately defended aposematic tadpole prey (the European common toad Bufo bufo) with varying absolute densities in single-species prey systems or varying relative densities in two-species prey systems containing morphologically similar but undefended prey (the European common frog Rana temporaria). The density effects were investigated in conjunction with the hunger levels of the predator, which were manipulated by means of the addition of alternative (nontadpole) food. The survival of the B. bufo tadpoles was promoted by increasing their absolute density in the single-species prey systems, increasing their relative density in the two-species prey systems, and providing ample alternative food for the predator. Hungry predators eliminated all R. temporaria individuals regardless of their proportion in the prey community; in treatments with ample alternative food, high relative B. bufo density supported R. temporaria survival. The results demonstrated that moderately defended prey did benefit from high population densities (both absolute and relative), even under long-term predation pressure. However, the physiological state of the predator was a crucial factor in the survival of moderately defended prey. While the availability of alternative prey in general should promote the spread and maintenance of aposematism, the results indicated that the resemblance between the co-occurring defended and undefended prey may impose mortality costs on the defended model species, even in the absence of actual mimicry.
Collapse
Affiliation(s)
- Jan M. Kaczmarek
- Department of ZoologyPoznań University of Life SciencesPoznańPoland
| | | | - Jan Mazurkiewicz
- Department of Inland Fisheries and AquaculturePoznań University of Life SciencesPoznańPoland
| | | |
Collapse
|
6
|
Palmer TM, Riginos C, Milligan PD, Hays BR, Pietrek AG, Maiyo NJ, Mutisya S, Gituku B, Musila S, Carpenter S, Goheen JR. Frenemy at the gate: Invasion by Pheidole megacephala facilitates a competitively subordinate plant ant in Kenya. Ecology 2020; 102:e03230. [PMID: 33098658 DOI: 10.1002/ecy.3230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 07/17/2020] [Accepted: 09/14/2020] [Indexed: 11/11/2022]
Abstract
Biological invasions can lead to the reassembly of communities and understanding and predicting the impacts of exotic species on community structure and functioning are a key challenge in ecology. We investigated the impact of a predatory species of invasive ant, Pheidole megacephala, on the structure and function of a foundational mutualism between Acacia drepanolobium and its associated acacia-ant community in an East African savanna. Invasion by P. megacephala was associated with the extirpation of three extrafloral nectar-dependent Crematogaster acacia ant species and strong increases in the abundance of a competitively subordinate and locally rare acacia ant species, Tetraponera penzigi, which does not depend on host plant nectar. Using a combination of long-term monitoring of invasion dynamics, observations and experiments, we demonstrate that P. megacephala directly and indirectly facilitates T. penzigi by reducing the abundance of T. penzigi's competitors (Crematogaster spp.), imposing recruitment limitation on these competitors, and generating a landscape of low-reward host plants that favor colonization and establishment by the strongly dispersing T. penzigi. Seasonal variation in use of host plants by P. megacephala may further increase the persistence of T. penzigi colonies in invaded habitat. The persistence of the T. penzigi-A. drepanolobium symbiosis in invaded areas afforded host plants some protection against herbivory by elephants (Loxodonta africana), a key browser that reduces tree cover. However, elephant damage on T. penzigi-occupied trees was higher in invaded than in uninvaded areas, likely owing to reduced T. penzigi colony size in invaded habitats. Our results reveal the mechanisms underlying the disruption of this mutualism and suggest that P. megacephala invasion may drive long-term declines in tree cover, despite the partial persistence of the ant-acacia symbiosis in invaded areas.
Collapse
Affiliation(s)
- Todd M Palmer
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA.,Mpala Research Centre, Box 555, Nanyuki, Kenya
| | - Corinna Riginos
- The Nature Conservancy, Lander, Wyoming, 82520, USA.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Patrick D Milligan
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA.,Mpala Research Centre, Box 555, Nanyuki, Kenya
| | - Brandon R Hays
- Mpala Research Centre, Box 555, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
| | - Alejandro G Pietrek
- Department of Biology, University of Florida, Gainesville, Florida, 32601, USA.,Mpala Research Centre, Box 555, Nanyuki, Kenya.,Instituto de Bio y Geociencias del NOA (IBIGEO), Salta, Argentina
| | - Nelly J Maiyo
- Conservation Department, Ol Pejeta Conservancy, Private Bag-10400, Nanyuki, Kenya
| | - Samuel Mutisya
- Conservation Department, Ol Pejeta Conservancy, Private Bag-10400, Nanyuki, Kenya
| | - Benard Gituku
- Conservation Department, Ol Pejeta Conservancy, Private Bag-10400, Nanyuki, Kenya
| | - Simon Musila
- Mammalogy Section, National Museums of Kenya, Nairobi, Kenya
| | - Scott Carpenter
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut, 06520, USA
| | - Jacob R Goheen
- Mpala Research Centre, Box 555, Nanyuki, Kenya.,Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, 82071, USA
| |
Collapse
|
7
|
Hammond TT, Ortiz-Jimenez CA, Smith JE. Anthropogenic Change Alters Ecological Relationships via Interactive Changes in Stress Physiology and Behavior within and among Organisms. Integr Comp Biol 2020; 60:57-69. [PMID: 31960928 DOI: 10.1093/icb/icaa001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Anthropogenic change has well-documented impacts on stress physiology and behavior across diverse taxonomic groups. Within individual organisms, physiological and behavioral traits often covary at proximate and ultimate timescales. In the context of global change, this means that impacts on physiology can have downstream impacts on behavior, and vice versa. Because all organisms interact with members of their own species and other species within their communities, the effects of humans on one organism can impose indirect effects on one or more other organisms, resulting in cascading effects across interaction networks. Human-induced changes in the stress physiology of one species and the downstream impacts on behavior can therefore interact with the physiological and behavioral responses of other organisms to alter emergent ecological phenomena. Here, we highlight three scenarios in which the stress physiology and behavior of individuals on different sides of an ecological relationship are interactively impacted by anthropogenic change. We discuss host-parasite/pathogen dynamics, predator-prey relationships, and beneficial partnerships (mutualisms and cooperation) in this framework, considering cases in which the effect of stressors on each type of network may be attenuated or enhanced by interactive changes in behavior and physiology. These examples shed light on the ways that stressors imposed at the level of one individual can impact ecological relationships to trigger downstream consequences for behavioral and ecological dynamics. Ultimately, changes in stress physiology on one or both sides of an ecological interaction can mediate higher-level population and community changes due in part to their cascading impacts on behavior. This framework may prove useful for anticipating and potentially mitigating previously underappreciated ecological responses to anthropogenic perturbations in a rapidly changing world.
Collapse
Affiliation(s)
- Talisin T Hammond
- San Diego Zoo Institute for Conservation Research, Escondido, CA 92027, USA
| | - Chelsea A Ortiz-Jimenez
- Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA
| | | |
Collapse
|
8
|
Smart AS, Tingley R, Phillips BL. Estimating the benefit of quarantine: eradicating invasive cane toads from islands. NEOBIOTA 2020. [DOI: 10.3897/neobiota.60.34941] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Islands are increasingly used to protect endangered populations from the negative impacts of invasive species. Quarantine efforts on islands are likely to be undervalued in circumstances in which a failure incurs non-economic costs. One approach to ascribe monetary value to such efforts is by modeling the expense of restoring a system to its former state. Using field-based removal experiments on two different islands off northern Australia separated by > 400 km, we estimate cane toad densities, detection probabilities, and the resulting effort needed to eradicate toads from an island. We use these estimates to conservatively evaluate the financial benefit of cane toad quarantine across offshore islands prioritized for conservation management by the Australian federal government. We calculate density as animals per km of freshwater shoreline, and find striking concordance of density estimates across our two island study sites: a mean density of 352 [289, 466] adult toads per kilometre on one island, and a density of 341 [298, 390] on the second. Detection probability differed between our two study islands (Horan Island: 0.1 [0.07, 0.13]; Indian Island: 0.27 [0.22, 0.33]). Using a removal model and the financial costs incurred during toad removal, we estimate that eradicating cane toads would, on average, cost between $22 487 [$14 691, $34 480] (based on Horan Island) and $39 724 [$22 069, $64 001] AUD (Indian Island) per km of available freshwater shoreline. We estimate the remaining value of toad quarantine across islands that have been prioritized for conservation benefit within the toads’ predicted range, and find the net value of quarantine efforts to be $43.4 [28.4–66.6] – $76.7 [42.6–123.6] M depending on which island dataset is used to calibrate the model. We conservatively estimate the potential value of a mainland cane toad containment strategy – to prevent the spread of toads into the Pilbara Bioregion – to be $80 [52.6–123.4] – $142 [79.0–229.0] M. We present a modeling framework that can be used to estimate the value of preventative management, via estimating the length and cost of an eradication program. Our analyses suggest that there is substantial economic value in cane toad quarantine efforts across Australian offshore islands and in a proposed mainland containment strategy.
Collapse
|
9
|
Affiliation(s)
- Mattia Falaschi
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 26, Milano 20133, Italy
| | - Andrea Melotto
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 26, Milano 20133, Italy
| | - Raoul Manenti
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 26, Milano 20133, Italy
| | - Gentile Francesco Ficetola
- Department of Environmental Science and Policy, Università degli Studi di Milano, Via Celoria 26, Milano 20133, Italy
| |
Collapse
|
10
|
Toads phenotypically adjust their chemical defences to anthropogenic habitat change. Sci Rep 2019; 9:3163. [PMID: 30816222 PMCID: PMC6395641 DOI: 10.1038/s41598-019-39587-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/23/2019] [Indexed: 01/07/2023] Open
Abstract
Despite the well-documented effects of human-induced environmental changes on the morphology, physiology, behaviour and life history of wild animals, next to nothing is known about how anthropogenic habitats influence anti-predatory chemical defence, a crucial fitness component of many species. We investigated the amount and composition of defensive toxins in adult common toads (Bufo bufo) captured in natural, agricultural and urban habitats, and in their offspring raised in a common-garden experiment. We found that, compared to toads captured from natural habitats, adults from both types of anthropogenic habitats had larger toxin glands (parotoids) and their toxin secretion contained higher concentrations of bufagenins, the more potent class of bufadienolide toxins. Furthermore, urban toads had lower concentrations of bufotoxins, the compounds with lower toxicity. None of these differences were present in the captive-raised juveniles; instead, toadlets originating from agricultural habitats had smaller parotoids and lower bufotoxin concentrations. These results suggest that toads' chemical defences respond to the challenges of anthropogenic environments via phenotypic plasticity. These responses may constitute non-adaptive consequences of pollution by endocrine-disrupting chemicals as well as adaptive adjustments to the altered predator assemblages of urban and agricultural habitats.
Collapse
|
11
|
A matter of proportion? Associational effects in larval anuran communities under fish predation. Oecologia 2018; 187:745-753. [PMID: 29713808 PMCID: PMC6018579 DOI: 10.1007/s00442-018-4141-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 04/13/2018] [Indexed: 11/13/2022]
Abstract
In Batesian mimicry, a species lacking defences against predators benefits from mimicking the aposematic signal of a defended species, while the model may incur the costs of reduced defensive efficacy. Similar reciprocal indirect effects may emerge even when the signal is not mimicked; termed associational effects, such interactions are well known in plants sharing herbivores but have received little attention in animal studies. We investigated associational interactions in a system where unequally defended prey (chemically defended Bufo bufo and undefended Rana temporaria tadpoles), sharing general morphology but not an aposematic signal, were exposed to predation by the carp Cyprinus carpio along a gradient of relative prey abundance. In the absence of fish, the assemblage composition had no effect on the survival of Rana, while that of Bufo decreased with increasing abundance of Rana. Fish reduced the survival of tadpoles from both species. However, increased relative abundance of Bufo in the community led to enhanced survival in both Bufo and Rana. Increasing relative proportions of heterospecifics reduced metamorph mass only in Bufo, indicating greater sensitivity to interspecific competition compared to Rana; the effect was reduced in the presence of fish. Our results show that undefended non-mimetic prey enjoy reduced predation with increasing relative abundance of chemically defended prey, which in turn suffer greater mortality with an increasing proportion of the undefended species. Associational resistance/susceptibility, driven by current assemblage composition, not by selection for resemblance, can shape the dynamics of mixed communities of defended and undefended prey in the absence of mimicry.
Collapse
|
12
|
Birnie-Gauvin K, Peiman KS, Raubenheimer D, Cooke SJ. Nutritional physiology and ecology of wildlife in a changing world. CONSERVATION PHYSIOLOGY 2017; 5:cox030. [PMID: 28740638 PMCID: PMC5516125 DOI: 10.1093/conphys/cox030] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 04/12/2017] [Accepted: 05/08/2017] [Indexed: 05/19/2023]
Abstract
Over the last century, humans have modified landscapes, generated pollution and provided opportunities for exotic species to invade areas where they did not evolve. In addition, humans now interact with animals in a growing number of ways (e.g. ecotourism). As a result, the quality (i.e. nutrient composition) and quantity (i.e. food abundance) of dietary items consumed by wildlife have, in many cases, changed. We present representative examples of the extent to which vertebrate foraging behaviour, food availability (quantity and quality) and digestive physiology have been modified due to human-induced environmental changes and human activities. We find that these effects can be quite extensive, especially as a result of pollution and human-provisioned food sources (despite good intentions). We also discuss the role of nutrition in conservation practices, from the perspective of both in situ and ex situ conservation. Though we find that the changes in the nutritional ecology and physiology of wildlife due to human alterations are typically negative and largely involve impacts on foraging behaviour and food availability, the extent to which these will affect the fitness of organisms and result in evolutionary changes is not clearly understood, and requires further investigation.
Collapse
Affiliation(s)
- Kim Birnie-Gauvin
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, Canada ON K1S 5B6
- DTU AQUA, National Institute of Aquatic Resources, Section for Freshwater Fisheries Ecology, Technical University of Denmark, Vejlsøvej 39, 8600 Silkeborg, Denmark
| | - Kathryn S. Peiman
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, Canada ON K1S 5B6
| | - David Raubenheimer
- Faculty of Veterinary Science, The University of Sydney, Regimental Drive, Camperdown, NSW 2050, Australia
| | - Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental Science, Carleton University, 1125 Colonel By Drive, Ottawa, Canada ON K1S 5B6
| |
Collapse
|
13
|
Ward-Fear G, Thomas J, Webb JK, Pearson DJ, Shine R. Eliciting conditioned taste aversion in lizards: Live toxic prey are more effective than scent and taste cues alone. Integr Zool 2017; 12:112-120. [PMID: 27579495 DOI: 10.1111/1749-4877.12226] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conditioned taste aversion (CTA) is an adaptive learning mechanism whereby a consumer associates the taste of a certain food with symptoms caused by a toxic substance, and thereafter avoids eating that type of food. Recently, wildlife researchers have employed CTA to discourage native fauna from ingesting toxic cane toads (Rhinella marina), a species that is invading tropical Australia. In this paper, we compare the results of 2 sets of CTA trials on large varanid lizards ("goannas," Varanus panoptes). One set of trials (described in this paper) exposed recently-captured lizards to sausages made from cane toad flesh, laced with a nausea-inducing chemical (lithium chloride) to reinforce the aversion response. The other trials (in a recently-published paper, reviewed herein) exposed free-ranging lizards to live juvenile cane toads. The effectiveness of the training was judged by how long a lizard survived in the wild before it was killed (fatally poisoned) by a cane toad. Both stimuli elicited rapid aversion to live toads, but the CTA response did not enhance survival rates of the sausage-trained goannas after they were released into the wild. In contrast, the goannas exposed to live juvenile toads exhibited higher long-term survival rates than did untrained conspecifics. Our results suggest that although it is relatively easy to elicit short-term aversion to toad cues in goannas, a biologically realistic stimulus (live toads, encountered by free-ranging predators) is most effective at buffering these reptiles from the impact of invasive toxic prey.
Collapse
Affiliation(s)
- Georgia Ward-Fear
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Jai Thomas
- School of Veterinary and Life Sciences, Murdoch University, Western Australia, Australia
| | - Jonathan K Webb
- School of Life Sciences, University of Technology Sydney, Broadway, New South Wales, Australia
| | - David J Pearson
- Western Australian Department of Parks and Wildlife, Waneroo, Western Australia, Australia
| | - Richard Shine
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| |
Collapse
|
14
|
Wijethunga U, Greenlees M, Shine R. Far from home: responses of an American predator species to an American prey species in a jointly invaded area of Australia. Biol Invasions 2016. [DOI: 10.1007/s10530-016-1107-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
15
|
Long AK, Conner LM, Smith LL, Mccleery RA. Effects of an invasive ant and native predators on cotton rat recruitment and survival. J Mammal 2015. [DOI: 10.1093/jmammal/gyv121] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
16
|
Hartman R, Pope K, Lawler S. Factors mediating co-occurrence of an economically valuable introduced fish and its native frog prey. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2014; 28:763-772. [PMID: 24372671 DOI: 10.1111/cobi.12218] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 08/18/2013] [Indexed: 06/03/2023]
Abstract
Habitat characteristics mediate predator-prey coexistence in many ecological systems but are seldom considered in species introductions. When economically important introduced predators are stocked despite known negative impacts on native species, understanding the role of refuges, landscape configurations, and community interactions can inform habitat management plans. We measured these factors in basins with introduced trout (Salmonidae) and the Cascades frog (Rana cascadae) to determine, which are responsible for observed patterns of co-occurrence of this economically important predator and its native prey. Large, vegetated shallows were strongly correlated to co-occurrence, and R. cascadae larvae occur in shallower water when fish are present, presumably to escape predation. The number of nearby breeding sites of R. cascadae was also correlated to co-occurrence, but only when the western toad (Anaxyrus boreas) was present. Because A. boreas larvae are unpalatable to fish and resemble R. cascadae, they may provide protection from trout via Batesian mimicry. Although rescue-effect dispersal from nearby populations may maintain co-occurrence, within-lake factors proved more important for predicting co-occurrence. Learning which factors allow co-occurrence between economically important introduced species and their native prey enables managers to make better-informed stocking decisions.
Collapse
Affiliation(s)
- Rosemary Hartman
- Graduate Group in Ecology, University of California, Davis, One Shields Avenue, Davis, CA, 95616, U.S.A..
| | | | | |
Collapse
|
17
|
Pearson DJ, Webb JK, Greenlees MJ, Phillips BL, Bedford GS, Brown GP, Thomas J, Shine R. Behavioural responses of reptile predators to invasive cane toads in tropical Australia. AUSTRAL ECOL 2013. [DOI: 10.1111/aec.12102] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- David J. Pearson
- Department of Parks and Wildlife; Perth Western Australia Australia
| | - Jonathan K. Webb
- Biological Sciences A08; University of Sydney; Sydney NSW 2006 Australia
- School of the Environment; University of Technology Sydney; Sydney New South Wales Australia
| | | | - Benjamin L. Phillips
- Biological Sciences A08; University of Sydney; Sydney NSW 2006 Australia
- School of Marine and Tropical Biology; James Cook University; Townsville Queensland Australia
| | - Gavin S. Bedford
- Crocosaurus Cove; 58 Mitchell Street Darwin Northern Territory Australia
| | - Gregory P. Brown
- Biological Sciences A08; University of Sydney; Sydney NSW 2006 Australia
| | - Jai Thomas
- Biological Sciences A08; University of Sydney; Sydney NSW 2006 Australia
| | - Richard Shine
- Biological Sciences A08; University of Sydney; Sydney NSW 2006 Australia
| |
Collapse
|
18
|
Ricciardi A, Hoopes MF, Marchetti MP, Lockwood JL. Progress toward understanding the ecological impacts of nonnative species. ECOL MONOGR 2013. [DOI: 10.1890/13-0183.1] [Citation(s) in RCA: 451] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
|
19
|
Shine R. A review of ecological interactions between native frogs and invasive cane toads in Australia. AUSTRAL ECOL 2013. [DOI: 10.1111/aec.12066] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Richard Shine
- School of Biological Sciences A08; University of Sydney; Sydney New South Wales 2006 Australia
| |
Collapse
|
20
|
Llewelyn J, Schwarzkopf L, Phillips BL, Shine R. After the crash: How do predators adjust following the invasion of a novel toxic prey type? AUSTRAL ECOL 2013. [DOI: 10.1111/aec.12058] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- John Llewelyn
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
- Centre for Tropical Biodiversity and Climate Change; School of Marine and Tropical Biology; James Cook University; Townsville Queensland Australia
- Ecosystem Sciences; CSIRO; Townsville Queensland Australia
| | - Lin Schwarzkopf
- Centre for Tropical Biodiversity and Climate Change; School of Marine and Tropical Biology; James Cook University; Townsville Queensland Australia
| | - Benjamin L. Phillips
- Centre for Tropical Biodiversity and Climate Change; School of Marine and Tropical Biology; James Cook University; Townsville Queensland Australia
| | - Richard Shine
- School of Biological Sciences; University of Sydney; Sydney NSW 2006 Australia
| |
Collapse
|
21
|
Marion L. Is the Sacred ibis a real threat to biodiversity? Long-term study of its diet in non-native areas compared to native areas. C R Biol 2013; 336:207-20. [PMID: 23849724 DOI: 10.1016/j.crvi.2013.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/02/2013] [Accepted: 05/03/2013] [Indexed: 11/18/2022]
Affiliation(s)
- Loïc Marion
- UMR CNRS ECOBIO, Université de Rennes-1, Campus Beaulieu, 35042 Rennes cedex, France.
| |
Collapse
|
22
|
Brown GP, Ujvari B, Madsen T, Shine R. Invader impact clarifies the roles of top‐down and bottom‐up effects on tropical snake populations. Funct Ecol 2013. [DOI: 10.1111/1365-2435.12044] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Gregory P. Brown
- Biological Sciences University of Sydney Sydney NSW 2006 Australia
| | - Beata Ujvari
- School of Biological Sciences University of Wollongong Wollongong NSW 2522 Australia
| | - Thomas Madsen
- School of Biological Sciences University of Wollongong Wollongong NSW 2522 Australia
| | - Richard Shine
- Biological Sciences University of Sydney Sydney NSW 2006 Australia
| |
Collapse
|
23
|
Evolutionary responses to invasion: cane toad sympatric fish show enhanced avoidance learning. PLoS One 2013; 8:e54909. [PMID: 23372788 PMCID: PMC3553005 DOI: 10.1371/journal.pone.0054909] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 12/19/2012] [Indexed: 11/19/2022] Open
Abstract
The introduced cane toad (Bufo marinus) poses a major threat to biodiversity due to its lifelong toxicity. Several terrestrial native Australian vertebrates are adapting to the cane toad’s presence and lab trials have demonstrated that repeated exposure to B. marinus can result in learnt avoidance behaviour. Here we investigated whether aversion learning is occurring in aquatic ecosystems by comparing cane toad naïve and sympatric populations of crimson spotted rainbow fish (Melanotaenia duboulayi). The first experiment indicated that fish from the sympatric population had pre-existing aversion to attacking cane toad tadpoles but also showed reduced attacks on native tadpoles. The second experiment revealed that fish from both naïve and sympatric populations learned to avoid cane toad tadpoles following repeated, direct exposure. Allopatric fish also developed a general aversion to tadpoles. The aversion learning abilities of both groups was examined using an experiment involving novel distasteful prey items. While both populations developed a general avoidance of edible pellets in the presence of distasteful pellets, only the sympatric population significantly reduced the number of attacks on the novel distasteful prey item. These results indicate that experience with toxic prey items over multiple generations can enhance avoidance leaning capabilities via natural selection.
Collapse
|
24
|
Responses of Australian wading birds to a novel toxic prey type, the invasive cane toad Rhinella marina. Biol Invasions 2011. [DOI: 10.1007/s10530-011-9974-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
25
|
Nelson DWM, Crossland MR, Shine R. Foraging responses of predators to novel toxic prey: effects of predator learning and relative prey abundance. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18736.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
26
|
Toad’s tongue for breakfast: exploitation of a novel prey type, the invasive cane toad, by scavenging raptors in tropical Australia. Biol Invasions 2010. [DOI: 10.1007/s10530-010-9903-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
27
|
Shine R. The ecological impact of invasive cane toads (Bufo marinus) in Australia. QUARTERLY REVIEW OF BIOLOGY 2010; 85:253-91. [PMID: 20919631 DOI: 10.1086/655116] [Citation(s) in RCA: 403] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Although invasive species are viewed as major threats to ecosystems worldwide, few such species have been studied in enough detail to identify the pathways, magnitudes, and timescales of their impact on native fauna. One of the most intensively studied invasive taxa in this respect is the cane toad (Bufo marinus), which was introduced to Australia in 1935. A review of these studies suggests that a single pathway-lethal toxic ingestion of toads by frog-eating predators-is the major mechanism of impact, but that the magnitude of impact varies dramatically among predator taxa, as well as through space and time. Populations of large predators (e.g., varanid and scincid lizards, elapid snakes, freshwater crocodiles, and dasyurid marsupials) may be imperilled by toad invasion, but impacts vary spatially even within the same predator species. Some of the taxa severely impacted by toad invasion recover within a few decades, via aversion learning and longer-term adaptive changes. No native species have gone extinct as a result of toad invasion, and many native taxa widely imagined to be at risk are not affected, largely as a result of their physiological ability to tolerate toad toxins (e.g., as found in many birds and rodents), as well as the reluctance of many native anuran-eating predators to consume toads, either innately or as a learned response. Indirect effects of cane toads as mediated through trophic webs are likely as important as direct effects, but they are more difficult to study. Overall, some Australian native species (mostly large predators) have declined due to cane toads; others, especially species formerly consumed by those predators, have benefited. For yet others, effects have been minor or have been mediated indirectly rather than through direct interactions with the invasive toads. Factors that increase a predator's vulnerability to toad invasion include habitat overlap with toads, anurophagy, large body size, inability to develop rapid behavioral aversion to toads as prey items, and physiological vulnerability to bufotoxins as a result of a lack of coevolutionary history of exposure to other bufonid taxa.
Collapse
Affiliation(s)
- Richard Shine
- School of Biological Sciences A08, University of Sydney, NSW 2006, Australia.
| |
Collapse
|
28
|
NELSON DAVIDWM, CROSSLAND MICHAELR, SHINE RICHARD. Behavioural responses of native predators to an invasive toxic prey species. AUSTRAL ECOL 2010. [DOI: 10.1111/j.1442-9993.2010.02187.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|